Mounting and thermoinsulative jacket for vapor electric devices



G. E. INMAN May 26, 1936.

MOUNTING AND THERMOINSULATIVE JACKET FOR VAPOR ELECTRIC DEVICES Filed July 28, 1954 Fig. I.

Inventor: George E. Inman;

5 H i Attcrne Patented May 26, 1936 UNITED STATES PATENT: OFFICE MOUNTING AND mamornsuna'rrvn JACKET Foa varoa ELECTRIC navrcns GeorgelE. Inman, East Cleveland, Ohio, asslgnor to General Electric Company, a corporation of New York My invention relates to the mounting of vapor electric devices, and to thermoinsulativeenclosures or globes for such devices. The invention is particularly adapted and advantageous for glowdischarge devices, such as lamps, that contain a dimcultly vaporizable working substance, like sodium and some other metals, whose vapor pressure during operation is very low, and whose operating temperature must be high. Very usually,

- sodium vapor lamps and similar glow discharge devices contain a small amount of easily ionized gas, like neon, argon, etc., to assist in starting the sodium or other vapor discharge. Efil'cient operation of these lamps depends on an adequate vapor pressure of sodium or the like in them, and

this, in turn, depends on their temperature during operation. For sodium vapor lamps, the best emciency is obtained at a temperature around 250 C. The higher the lamp temperature, the more heat is radiated from the lamp in operation, and the more energy must be supplied to keep up the temperature and produce the desired amount of light. On this account, enclosure of the lamp in athermoinsulative but light permeable jacket I aim to provide for mounting and thermoinsulating such vapor electric devices in a simple and convenient way. Other features and advantages of the invention will appear from the following description of species thereof, and from the drawin In the drawing, Fig. 1 is a vertical sectional view of a lamp mounting suitable for the purposes of my invention, including a thermoinsulative globe, with a glow discharge vapor lamp particularly suitable for operation on alternating current therein; Fig. 2 is a similar view, with the lamp and certain other parts omitted, illustrating certain modifications of the globe and its holder; Fig. 3 is a fragmentary vertical sectional view of the upper portion of the globe, illustrating another modification thereof; and Fig. 4 is a similar view illustrating yet another modification of the globe.

Fig. 1 shows a globe and lamp holder 5 wherein is mounted a double-walled thermoinsulative globe 5 enclosing an electric glow discharge vapor lamp I, which is mounted in a lamp socket device 8 in the holder 5.

The lamp 1 comprises a bulb with a reduced neck 9, provided with base and contact terminal means III, II; astem l2; current lead wires l3, l3 sealed.

through the stem; and a pair of electrodes l4, [4, connected to the leads and supported by them, and (mechanically) interconnected by a wire I5.

The lamp bulb is shown with a fused exhaust tip or globe is desirable, in the interest of efliciency.

IS on its hemispherical bowl. The electrodes II, M are shown as of an indirectly heated (hollow) type, with electron-emissive surfacings of barium oxide or the like on nickel tube bases, and internal (tungsten) heating coil resistances l1, l1 ex- 5 tending centrally through the base tubes- In operation, the heating resistances l1, l1, serially connected (electrically) between the leads i3, i3 by the wire l5, are in parallel with the discharge gap between the electrodes I4, I, whose base tubes 10 are also connected to the leads l3,.l3. The lamp bulb contains a chargeof the diflicultly vaporizable working substance, such as sodium, and also, preferably, some easily ionized gas like neon. For various reasons, it is desirable to exclude the hot 15 sodium vapor from the bulb neck 9; and for this purpose a shut-ofi disc l8 (preferably suitably refractory and thermoinsulative) is shown forming a septum across the neck at its junction or merger with the rest of the bulb,which may be dis- 0 tinguished as the bulb proper." The current leads l3, l3 extend through holes in the disc l8, and these holes and the joint around the disc edge are sealed tight with suitable cement. A fine tube -19 extends through the disc l8, to permit the bulb 25 neck 9 to be exhausted through the bulb proper. The opening through the tube 19 is so fine as to be automatically closed or scaled up by sodium condensing in the tube when the lamp is first operated. Along with its other functions, the shut- 30 off i8 reduces the loss of heat by transmission via the bulb neck 9. y

The holder 5 is shown as a hollow structure of irregularly conical general outline, with a globereceiving mouth 20 having an internal globe- 35 abutting shoulder 2|. This holder 5 may advantageously be made as an aluminum casting. The lamp socket device 8 may be of any suitable type and construction, but is here shown as an Edison scre'w socket. The light-permeable vac- 4 uum jacket or globe 6 is removably secured in the mouth 20 of the holder 5, against its internal shoulder 2!. The engagement means of the globe 6 for this purpose consists of external screw threads 22 on its upper end, and the 45 corresponding securing means of the 'holder 5 consists of internal screw threads 23 in its mouth 20. The holder 5 has diametrically oprosite ears 24. 24, with tapped holes through them, for securing it to any desired means of support, when 50 desired. The shoulder 2| is preferably finished flat and true, and a gasket 25, which I prefer to make of soft but refractory thermoinsulative material like asbestos "felt or cloth, is interposed between the shoulder 2l andthe abutting 55 upper end of the globe 6, making a gas and vaportight joint. The insulating (bisque or porcelain) base 26 of the socket 8 is mounted in the central cavity of the holder 5, within and above the shoulder 2|; but its lamp-base receiving (screw) shell (marked 8) is mainly or entirely below the shoulder-2l. The socket base 26 is secured by screw-bolts 21 against the mid-portio .of a metal strip 28 whose ends are bent first downward and then outward, thus affording radial ears that overlap the shoulder 2 f and are secured against it by screws 29, 29 taking into suitably tapped holes in the metal of the holder 5. The socket leads 3|], 3| are connected as usual to the socket shell 8 and center contact 32, respectively, and extend up into a supporting tube or pipe 33 on whose lower end the holder 5 may be screwed fast, as shown. A thermoeinsulative refractory (asbestos) vacuum jacket gasket 35 is shown mounted around the lamp bulb neck 9 substantially or approximately in line with the shut-off l8, and against or around the bead at the merger of the neck 9 with the rest of the bulb. This gasket 35 fits snugly around the bulb neck 9 and against the interior surface of the globe 6; it may be made of a number of thicknesses of asbestos felt, to render it soft and conformative to the bulb neck and globe surfaces. The gasket 35 helps to minimize transmission of heat to the upper part of the globe 6 by conduction and con-' vection in the air inside the globe 6, around the lamp 1.

The details of holder 5, lamp 1, socket device 8, and their associated parts hereinbefore described are illustrative, and may be widely varied, or even radically changed.

The thermoinsulative or heat-conserving jacket or globe 6 shown in Fig. 1 is of double-walled construction, comprising outer andinner walls or globes 36, 31 everywhere suitably spaced apart, but united at 38 at their upper ends, above the screw threads 22 of the outer globe 36. As shown,

they are of cylindrical (inverted) bell-jar form,

with spherical bowls corresponding closely to the bowl of the lamp 1. They may be made separately (of glass) and afterward fused .or sealed together at 38. This portion 38 uniting them is preferably finished smooth and true so as to make a liquid and vapor-tight joint against the thermoinsulative gasket 25,thus preventing water or moisture from getting inside the whole jacket 6 and perhaps coming in contact with the envelope or bulb of the lamp .1 when hot, and causing it to crack. Indeed, the device is practically vapor and moisture proof at all. points. The inter-space of the double globe 6 may be evacuated and then hermetically sealed up, as indicated bythe fused exhaust tip 39 on the outer globe; or other thermoinsulative means may be used, and similarly ensealed in the interspace,-. such as a gas of low heat conductivitv. like carbon dioxide or argon. It will be seen that the extension of the vacuum space or other thermoinsulative means up inside the jacket screw threads 22 (due to the fact that the union 33 between the outer and inner globes 36, 31 is above the threads) tends to reduce or minimize transportion of the globe 6 surrounds the socket shell 8 and thus minimizes radiation of heat from said shell to the holder mouth 20.

In Fig. 2, the upper end of the outer wall or globe 36a of the double globe 6a is externally recessed and shouldered at 22a, instead of being screw threaded as in Fig. 1;. and the corresponding securing means of the globe-receiving mouth 20a of the holder 5a consists of (two or more) set-screws 23a threaded through the mouth wall. As shown, these screws 23a extend inward and upward at about a 45 angle to the vertical, and the mouth wall at 20a. is externally thickened and bevelled, and internally hollowed gt 23b, to facilitate thus mounting the screws 30. in it. Still? but somewhat yielding pads ll) may be interposed between the ends of the screws 23a and the glass surfaces at 22a which they engage, to protect the glass from breakage by careless tightening of the screws. Here the thermoconductive area of contact between the globe 6a and the holder 5a-represented entirely by the ends of the screws 23a and their pads 40, if three or more screws equally spaced are properly set up-- is much less than that of the globe threads 22 25 with the holder mouth threads 23 in Fig. 1; and thus the heat transmission from the globe to the holder is correspondingly well minimized.

Fig. 3 shows another form of 'double globe 6b adapted to be used in the holder 5 of Fig. 1.

Here the external screw threads 22 are on a single-walled (glass) skirt 31w attached to the uniting portion 38b of the upper ends of the outer and inner globes 36b, 31b. As a matter of manufacture, it is preferred to make this skirt 31w an integral part of the inner globe 37b in the first instance, and to provide this globe 31b with an external downward facing shoulder 31:: below its screw threads 22. This inner globe 31b may then be inserted in the outer globe 36b with the upper edge 36a: of the outer globe engaged against or around the shoulder 31m, and the edge 36:: may then be fused and sealed to the shoulder 31:: at 38b, as in Fig. 2. In the present instance, the shoulder 31:: is a rounded external ridge, formed by local annular expansion of the inner globe wall 31b, and is thus hollow.

In Fig. 4, the skirt 312 is a metal screw-shell with (external) threads 22 rolled or otherwise formed thereon, and it is suitably attached to either or both globes 36c, 3lc,-'or more accurately, to the fused union 38c of these outer and inner globes. The attachment need not necessarily be a cemented one, but may be effected by fusing the glass at 380 to or on the edge of the metal skirt 31a.

In Figs. 2, 3 and 4, various parts and features are marked with the same reference characters as the corresponding ones in Fig. 1 (with an added letter, where such distinction appears necessary) as a means of minimizing and avoiding repetitive description.

It may be further pointed out, however, that with any of the double globes 6, 6a, 6b, or 60, the shut-oi! l8 and the jacket gasket 35 form a deadline or thermoinsulative plane clear across the interior of the globe within its double-walled portion. This and the vacuum in the double globe wall coact with gasket 25 in minimizing transmission of heat to the holder 5. The shutofl l8 prevents transmission by convection (and conduction) in gas and vapor in the bulb neck 9; the gasket 35 prevents similar transmission via air inside globe 6; and the vacuum and the gasket 25 prevent the heat from outflanking" the deadline" at [8, 35.

What I claim as new and desire to secure by Letters Patent of the United States, is:

A lamp unit comprising in combination a gaseous electric discharge vapor lamp having an elongated, reduced neck, a two-contact screw base attached to the end of said neck and a shutofi means occluding said neck from the rest of the lamp bulb to exclude hot vapor from the neck; a double-walled globe surrounding said lamp to reduce the heat losses therefrom and having external screw threads adjacent the open end thereof; a gasket of heat insulating. material fitting around said lamp neck and against the internal surface of said double-vwalled globe substantially in line with said shut-01f means, and a globe and lamp holder having an internally threaded and shouldered globe-receiving mouth and a gasket of heat insulating material in said holder against said shoulder, a threaded, twocontact socket mounted on a thick support of thermally insulating material supported in said holder, the contact end of said socket being substantially in line with the shoulder in said holder; said globebeing screwed into said threaded holder mouth and resting against said gasket therein, said lamp base being screwed into said socket.

GEORGE E. INMAN'. 

